Cover accessory device for a portable electronic and/or computer apparatus, and apparatus provided with such an accessory device

ABSTRACT

The present invention relates to a device for a portable user apparatus, including a portion which can be folded over the user apparatus, said foldable portion including at least two detection layers, each kept at a guard potential and including at least one capacitive detection electrode: a first of said layers being arranged to carry out a function of capacitive detection of at least one control object located on one side of said foldable portion; a second of said layers being arranged so as to carry out a function of capacitive detection of at least one control object located on the other side of said foldable portion, with a view to triggering a function in the user apparatus. The invention also relates to an apparatus provided with such an accessory device.

TECHNICAL DOMAIN

The present invention relates to a covering accessory device for a portable electronic and/or computer apparatus, providing a function of detection of a command object. It also relates to a portable electronic and/or computer apparatus equipped with such an accessory device.

The domain of the invention is more specifically, but without limitation, that of contactless human-machine interfaces, implementing a capacitive detection technology, and still more specifically a capacitive detection technology implementing a guard plane for capacitive electrodes.

STATE OF THE ART

There are currently on the market many accessories aiming to cover portable electronic and/or computer apparatus, such as portable microcomputers, digital tablets or smart phones. These accessories generally have a function of protection against impacts and scratches and also aesthetic and personalization function. These accessories can come in various forms: sleeves, pockets, covers, flexible or rigid envelopes and shells.

Some of these accessories have a foldable flap intended to cover the screen and possibly the keyboard of portable apparatus. This flap protects the front surface of the portable apparatus when it is folded thereunto and opening it releases the screen and command functions.

Furthermore, more and more portable apparatus, such as tablets and smart phones are equipped with a touchscreen and provide Human-Machine Interface (HMI) functions. These apparatus use, as an interface, touchpads which are transparent on the screens and opaque in the area of a command surface arranged on the periphery of the screen. Most of these pads use capacitive technology. With this technology, one or more command objects (fingers, stylus, etc.) can be detected in contact with or at a distance from the command surface; this technology implements the capacitive technology described in the patents FR 2,893,711 or FR 2,949,007, or again in the patent application FR 2,971,666 A1, filed by the Applicant.

However, the detection functionality is currently limited to the electronic/computer apparatus. When this apparatus is provided with an accessory device comprising a movable part, such as for example a foldable protective cover, it is first necessary to handle the protective cover to leave access to the command surface and then to start to interact with the apparatus.

Additionally accessory devices, of protective cover with foldable flap type, are currently used to satisfy a single function which is apparatus protection.

An object of the present invention is to remedy the aforementioned disadvantages.

Another object of the present invention is to propose a protective accessory device for a computer/electronic apparatus providing more functionalities than currently known accessory devices.

Again another object of the present invention is to propose a protective accessory device for a computer/electronic apparatus contributing to, or even improving, the detection functionalities of such an apparatus.

Finally, it is an object of the present invention to propose a protective accessory device for a computer/electronic apparatus allowing a faster interaction and requiring less handling of said apparatus.

DESCRIPTION OF THE INVENTION

The invention proposes to achieve at least one of the aforementioned objects with a device for a portable electronic and/or computer apparatus, called user apparatus, where said device comprises a part which folds in order to cover at least one part of said user apparatus when it is folded onto said user apparatus, characterized in that said foldable part comprises at least 2 detection layers, each guarded at one guard potential and comprising at least one, preferably several, capacitive detection electrode(s):

-   -   a first of said layers being arranged to perform a capacitive         detection function of at least one command object located on one         side of said foldable part, in particular the side of the inner         surface of said foldable part located on the side of said user         apparatus when it is folded onto said user apparatus;     -   a second of said layers being arranged to perform a capacitive         detection function of at least one command object located on the         other side of said foldable part, in particular the side of the         outer surface of said foldable part when it is folded onto said         user apparatus;         in order to trigger a function in said user apparatus.

In that way, one has a device, and more precisely an accessory device, with which to perform a capacitive detection function for a portable apparatus while also performing a removable protective cover function. In that way, a compact and operational equipment results whatever the effective position of the foldable part. Consequently, the device according to the invention provides more functionalities than the accessory devices from the state-of-the-art which only provide a protective function for the user apparatus.

Additionally, with the device according to the invention, it is possible to detect a command object even when the foldable part of the device is folded onto the apparatus and to trigger a function done by the user apparatus. In that way, it is possible to interact with the user apparatus without having to handle the foldable part of the device, allowing a faster interaction with less handling for the user.

The device according to the invention serves to perform a detection of a command object by a layer of guarded capacitive electrodes, which allows an improved detection of the command object.

Furthermore, the device according to the invention serves to perform a detection of a command object whatever the position of the foldable part, in that way offering the user more freedom in the positioning of the foldable part and consequently in the control of their apparatus. In fact, with the device according to the invention, the user can trigger a function in the user apparatus, whatever the position of the movable part.

Preferably, the detection layers are not coplanar, each of the detection layers forming a plane substantially parallel to the plane defined by the foldable part and/or the plane defined by at least one other detection layer.

The electrodes from at least one, preferably each, detection layer can perform an autonomous detection, in “self-detection” mode or a detection by cooperating with another electrode, in “mutual-detection” mode.

In a preferred, but in no way limiting, version one of the capacitive electrode layers is parallel to the surface of the user apparatus serving to form a display and/or comprising a touchpad provided with capacitive electrodes when the movable part is folded onto the user apparatus.

In a preferred, but in no way limiting, version the first capacitive electrode layer is also called “inner layer” and is arranged on the side of a surface, called inner, of the foldable part coming into contact with the user apparatus when the foldable part is folded onto the user apparatus, and the second layer of capacitive electrodes is also called “outer layer” and is arranged on the side of a surface called outer opposite said inner surface.

In a particular embodiment, for at least one position and/or at least one given moment, both detection layers can be activated in detection. In this case, for at least one given moment or at least one given position of the foldable part, the device according to the invention performs a detection near both surfaces of the foldable part.

According to an advantageous embodiment, each of said first and second layers can be activated in detection in turn, depending upon the relative position of the foldable part with respect to the user apparatus such that for a given position of said foldable part just one of said layers performs the detection function.

For example, when the foldable part is completely folded back onto the apparatus, only the outer layer may be activated in detection and when the foldable part is completely open only the inner layer may be activated in detection. More generally, when the foldable part has an angle β less than or equal to a preset first threshold value, only the outer layer can be activated in detection, and when the foldable part has an angle β greater than or equal to a preset second threshold value, only the inner layer can be activated in detection.

Of course, the first and second threshold values can be identical or different. The threshold value or values can be included between 45° and 135°, and in particular equal to 90°.

Alternatively, the activation in detection (respectively deactivation from detection) of at least one, preferably of each, detection layer can be done either by the user or by the user apparatus or even by a human-machine interface, or more generally an application running on the user apparatus. In this case, activation in detection (respectively deactivation from detection) is done, not as a function of the angle between the foldable part and the user apparatus, but by the user or by an application running on the user apparatus.

According to a first implementation version, the device according to the invention can further comprise at least one guard plane arranged between the first and second detection layers and placed at guard potential in order to guard at least one of said first and second detection layers during the detection of at least one command object.

In this case, the one or each guard plane is arranged between the detection layers.

The device according to the invention may comprise a dedicated guard plane for each detection layer.

According to an advantageous alternative of this first implementation version, the device according to the invention may comprise a single guard plane arranged between the first and second detection layers in order to guard each of said detection layers. Thus, with a single guard plane, the device according to the invention serves to guard two different detection layers.

According to a second particularly advantageous and preferred implementation version, the device according to the invention does not include a guard plane in addition to the detection layers. In this second version, each of the first and second detection layers performs in turn the role of:

-   -   either the detection function;     -   or a guard function for the other of said capacitive detection         layers by being placed at an alternating potential (V_(G)),         called guard;         the function performed by each of said layers depending on the         relative position of said foldable part relative to said user         apparatus.

In that way, when one of the detection layers is used in detection, the other of the detection layers is used as guard plane, and vice versa. In this version, the device according to the invention serves to avoid the use of a guard plane in addition to the detection planes. In that way, the device according to the invention has a more compact architecture and is less complex and less costly to implement.

In that way, the device according to the invention automatically adapts and changes the respective functions of the electrode layers equipping the foldable part, and in particular the inner surface and outer surface of the foldable part.

For example, when the movable part is folded back: the inner layer can be set up to implement the guard function and the outer layer can be set up to implement the detection function and when the movable part is open and reaches an angle greater than a set angle relative to a surface of the apparatus: the inner layer can be set up to provide the detection function and the outer layer can be set up to provide the guard function.

In other words, and more generally, the inner layer and the outer layer can be set up such that the function done by each layer is chosen depending on the angle β between the movable part and the user apparatus, such that:

-   -   when β is less than a first set value, the inner layer provides         a guard function and the outer layer provides a detection         function, and     -   when β is greater than a second set value, the inner layer         provides a detection function and the outer layer provides a         guard function.

Of course, the first and second threshold values can be identical or different. The threshold value or values can be included between 45° and 135°, and in particular equal to 90°.

Alternatively, the activation (respectively the deactivation) in detection or in guard of at least one, preferably of each, detection layer can be done either by the user or by the user apparatus or even by a human-machine interface, or more generally an application running on the user apparatus. In this case, the functions (detection or guard) of each layer are decided not according to the angle of the folded part relative to the user apparatus, but by the user or by an application running on the user apparatus.

Advantageously, the respective electrodes of each layer can be arranged so as to substantially mask each other. It can advantageously be the same for the respective connecting tracks of each detection layer which have to substantially mask each other.

The device according to the invention can further advantageously comprise at least one means of control in order to determine, depending on the position of the foldable part, which of the electrode layers of the foldable part must implement the detection function and in order to activate the electrodes from said detection layer in measurement mode.

When the other detection layer is used as guard for guarding the layer activated in detection, the means of control can further be arranged in order to control placing the electrodes from the other electrode layer at guard potential so as to have the latter perform the guard function.

Advantageously, the control means can be coupled to, or include, a means of detection/measurement of the position of the foldable part, such as for example a means for measurement of the angle between the foldable part and the user apparatus.

The means of detection can be performed by, or include at least, one electrode, located on the inner surface of the foldable part and in particular at least one of the electrodes from the inner detection layer, targeting the user apparatus and arranged in order to measure the distance between the user apparatus and said foldable part. In that way, according to the distance measured by such an electrode, it is possible to determine the position of the foldable part.

Alternatively, if the mobile apparatus is equipped with a layer of detection electrodes, for example arranged in/on a display screen, it is also possible to use at least one electrode from the detection layer of said apparatus in order to determine the position of the foldable part. To do this, it is sufficient to activate the electrodes measuring the distance between the foldable part and the user apparatus and deactivate the targeted electrodes, at least during the measurement time, or to use different excitation frequencies on the different layers so that the electrodes from several detection layers do not disrupt each other.

Advantageously, at least one layer of electrodes is arranged in order to perform a detection of at least one command object with or without contact. In this way, the device according to the invention performs a capacitive command detection function which can be “multitouch” and/or “touchless” type.

The device according to the invention can be removable and include, at least one means of connection to the user apparatus.

This means of connection can be arranged to implement a wired or wireless connection with the user apparatus.

According to an implementation example which is in no way limiting, the means of connection can, for example, be incorporated in a portion of shell of the device according to the invention, connected to the foldable part and arranged in order to be substituted for or arranged on a rear shell of the user apparatus.

The device according to the invention can alternatively be non-removable and be an integral part of the user apparatus.

In a preferred implementation example, the foldable part of the device according to the invention may comprise a transparent area allowing visual access to a zone of the user apparatus such as a display screen or a portion of a display screen. In that way, it is possible to view a display screen from the user apparatus while interacting with the user apparatus by means of the device according to the invention, without having to open the foldable part.

When the device according to the invention is implemented for a user apparatus comprising a display screen, the foldable part, and in particular the transparent area of the foldable part, can be configured in order to be positioned on or against said screen when it is folded.

In this case at least one, preferably each, detection layer can include, at said transparent area level, electrodes made of a transparent material, for example in “Indium Tin Oxide” ITO technology, in order to conserve visual transparency around the transparent zone.

Alternatively, the transparent zone might not be provided with electrodes.

The foldable part may alternatively or additionally comprise an opaque area. In this case, at least one, preferably each, of the detection layers can include, at said opaque area level, electrodes made with PCB, Printed Circuit Board, technology.

In a specific configuration of an accessory according to the invention, the foldable part acting as a cover is arranged in order to provide in deployed capacitive detection area substantially in the extension of the screen of the user apparatus. This configuration in particular provides the user a possibility of control without Joystick type contact sought by some game consoles.

Advantageously the foldable part has a thickness greater than or equal to 0.5 mm.

According to another aspect of the invention, a portable electronic and/or computer apparatus comprising an accessory device according to the invention is proposed.

This portable apparatus according to the invention can be provided with a rear shell which is advantageously substituted by a rear shell part of an accessory device according to the invention.

The portable apparatus can comprise a display screen and the foldable part of the device according to the invention can be positioned so as to fold at least in part over said display screen.

The apparatus according to the invention may be a computer, telephone or smart phone, a game console, a PDA, a touch tablet, etc.

DESCRIPTION OF THE FIGURES AND EMBODIMENTS

Other advantages and features will appear from an examination of the detailed description of examples which are in no way limiting and of the attached drawings on which:

FIGS. 1-3 are schematic representations of the device according to the invention in three different configurations.

FIGS. 4-6 are schematic representations, in section view, of three implementation examples of a foldable part of a device according to the invention.

FIG. 7 is a schematic representation of a control module for a device according to the invention.

FIG. 8 is a schematic representation of the operation of the foldable part shown in FIG. 6; and

FIGS. 9-11 are schematic representations of an apparatus according to the invention, in which a portion of the device according to the invention is substituted for a rear shell of said user apparatus.

It is well understood that the embodiments which will be described in the following are in no way limiting. One could in particular imagine variants of the invention only comprising a selection of features subsequently described isolated from other features described, if this selection of features is sufficient to confer a technical advantage or for distinguishing the invention from the state of the prior art. This selection includes at least one preferably functional feature without structural details, or with only a portion of the structural details, if this part alone is sufficient to give a technical advantage or to distinguish the invention compared to the state of the prior art.

In particular, all the variants and all the embodiments described can be combined with each other if at the technical level nothing prevents it.

In the figures, the elements common to several figures retain the same reference.

We are now going to describe different examples of an electronic/computer device according to the invention implementing different embodiments of an accessory device according to the invention.

FIGS. 1 to 3 are schematic representations of a nonlimiting example of a device 100 according to the invention for user apparatus 102 such as a smart Phone® or a digital tablet.

The device 100 comes in the form of a protective cover for the user apparatus 102 and comprises a part 104 foldable relative to the user apparatus and a part 106 fixed relative to the user apparatus.

The fixed part 106 functions as a shell for the rear of the user apparatus 102 and envelops the user apparatus 102.

The foldable part 104 is mechanically connected to the fixed part 106 by a flexible connection 108 and can be rotated around this flexible connection 108 in order to be opened or be folded against the user apparatus 102. The foldable part 104 is intended to cover the screen 110 of the apparatus 102 in folded position. In FIG. 1, the foldable part 104 is open so as to form an angle β substantially equal to 135° with the plane formed by the screen 110 of the user apparatus 102. In FIG. 2, the foldable part 104 is open so as to form an angle β substantially equal to 180° with the plane formed by the screen 110 of the user apparatus 102. In FIG. 3, the foldable part 104 is closed or in folded position so as to form an angle β substantially equal to 0° with the plane formed by the screen 110 of the user apparatus 102.

FIGS. 4-6 are schematic representations, according to a section view, of three implementation examples of a foldable part 104.

Whatever the embodiment, the foldable part 104 comprises:

-   -   a carrying structure 402;     -   an inner surface 404 provided for coming into contact with the         user apparatus 102, and more specifically the screen 110 of the         user apparatus, when the foldable part 104 is completely folded,         such as shown in FIG. 3; and     -   an outer surface 406 opposite the inner surface 404.

The inner surface 404 comprises a detection layer 408, called inner, formed by a set of capacitive detection electrodes (not shown) and the outer surface 406 comprises a detection layer 410, called outer, formed by a set of capacitive detection electrodes (not shown). Each detection layer 408 and 410 is provided and laid out in order to implement detection, with or without contact, of one or more command objects such as a finger, hand or stylus. Connecting tracks (not shown) are associated with each of the detection layers 408 and 410.

When the foldable part comprises a transparent area made of transparent material, the electrodes for each of the detection layers 408 and 410 and the connecting tracks which are found at the transparent area level are made using ITO (“Indium Tin Oxide”) technology. When the foldable part 102 is completely opaque, the detection electrodes and connecting tracks are made with PCB (“Printed Circuit Board”) type technologies, flexible or rigid, surrounded or not with a dielectric for protection.

In the example shown in FIG. 4, the foldable part 104 ₁ further comprises a guard plane 412, called inner, associated with the inner detection layer 408 and provided for guarding the electrodes of said inner layer 408 when this layer is used for detecting one or more command objects. The foldable part 104 ₁ also comprises a guard plane 414, called outer, associated with the outer detection layer 410 and provided for guarding the electrodes of said outer layer 410 when the latter is used for detecting one or more command objects. Each guard plane 412 and 414 is placed at an alternating potential V_(G), of a given frequency.

In the example shown in FIG. 5, the foldable part 104 ₂ comprises a single guard plane 502 shared by the inner 408 and outer 410 detection layers. This single guard plane 502 is placed at an alternating guard potential V_(G), of a given frequency and serves to guard each of the detection layers 408 and 410.

In the example shown in FIG. 6, the foldable part 104 ₃ comprises only the inner detection layers 408 and 410 and does not comprise a guard plane in addition to the detection layers 408 and 410. In this embodiment, when one of the detection layers 408 and 410 is used in detection, the other one of the detection layers 410 and 408 is used in order to form a guard by being placed at a guard potential and in that way guarding the detection layer activated in detection.

FIG. 7 is a schematic representation in diagram form of an example control and command module of a device according to the invention, controlling the components of the foldable part.

The module 700 shown in FIG. 7 comprises one control unit 702 in communication with the user apparatus 102 because of a wired or wireless means of communication 704.

The module 700 comprises or is associated with one or more sensors 706, such as one or more optical, capacitive, mechanical or magnetic sensors measuring an angle, a distance or a movement serving to determine the relative position of the foldable part 102 compared to the user apparatus 102.

The control unit is configured to receive signals from a part of the user apparatus 104 and sensors 706, process the received signals and control the detection layers 408 and 410 and possibly the guard planes 412, 414 and 502.

Additionally, the control unit 702 is also configured for receiving signals from each of the detection layers 408 and 410 and informing the user apparatus 102 of the one or more positions of the one or more command objects detected by each of the detection layers 408 and 410.

We are now going to describe the operation of the control unit 702, when the device comprises the foldable part 104 ₁ shown in FIG. 4.

In a first variant, the control unit 702 can activate the inner 408 and outer 410 layers in detection at any time: in this case, the layers 408 and 410 perform a detection function for one or more command objects whatever the relative position of the foldable part 1041 compared to the user apparatus 102. In this first variant the guard planes 412 and 414 are also activated at any moment and perform the guard function.

In a second variant, the activation of the detection layers 408 and 410 is done as a function of the relative position of the foldable part 104 ₁ relative to the user apparatus. In this variant, depending on the relative position of the foldable part 104 ₁ relative to the user apparatus, each of the detection layers 408 and 410 is activated or not. More generally:

-   -   when the foldable part 104 ₁ has an angle β less than or equal         to a first set threshold value β₁, the control unit 700         deactivates the inner layer 408 and only the outer layer 410 is         activated in detection; and     -   when the foldable part 104 ₁ has an angle β greater than or         equal to a second set threshold value β₂, the outer layer 410 is         deactivated and only the inner layer is activated in detection.

The guard planes 412 and 414 associated respectively with the inner layer 408 and the outer layer can be activated and deactivated at the same time as the layer with which they are associated.

Of course, the first threshold value β₁ can be identical, greater than or less than the second threshold value β₂. Each threshold value is included between 45° and 135°, and in particular is equal to 90°.

We are now going to describe the operation of the control unit 702, when the device comprises the foldable part 104 ₂ shown in FIG. 5.

In order to control the foldable part 104 ₂, the control unit 702 can implement the two control variants described above for the control part 104 ₁, with the difference that the single guard plane 502 is activated when at least one of the detection layers 408 and 410 is activated.

We are now going to describe the operation of the control unit 702, when the device comprises the foldable part 104 ₃ shown in FIG. 6.

The control unit 702 commands the two detection layers 408 and 410, either in “capacitive detection” function, or in “electrostatic guard” function. In that way, each of the two surfaces 404 and 406 of the foldable part 104 ₃ is alternately a detection surface and a guard surface, depending on the position of the foldable part 104 ₃, such as shown in FIG. 8.

In that way, when one of the detection layers is used in detection, the other detection layer is used as guard plane, and vice versa. For example, when the movable part 104 ₃ is folded back: the inner layer 408 is commanded to perform the guard function by being placed at guard potential by the control unit 702 and the outer layer 410 is commanded to perform the detection function, and when the movable part 104 ₃ is open and reaches an angle greater than a set angle relative to the surface of the apparatus 102: The inner layer 408 is commanded to perform the detection function and the outer layer 410 is commanded to perform the guard function by being placed by the control unit 702 at the guard potential.

In other words, and more generally, the inner layer 408 and the outer layer 410 are set up such that the function done by each layer is chosen depending on the angle β between the foldable part 104 ₃ and the user apparatus 102, such that:

-   -   when β is less than a first set value β₁, the inner layer 408         performs a guard function and the outer layer 410 performs a         detection function, and     -   when β is greater than a second set value β₂, the inner layer         408 performs a detection function and the outer layer 410         performs a guard function.

Of course, the first and second threshold values can be identical or different. The threshold value or values can be included between 45° and 135°, and in particular equal to 90°.

In general, in all the embodiments described, when a detection layer is not used/activated in detection, for example because it is deactivated or activated in guard, at least one of the electrodes from this layer can be used sporadically, on request or at a set frequency, in order to detect the presence of objects opposite the surface associated with said detection layer and the type of object detected (for example a table when it involves the outer surface, a display screen when it involves the inner surface, etc.).

We are now going to describe a user apparatus according to the invention.

FIGS. 9-11 are schematic representations of an example implementation of a apparatus according to the invention provided with a device according to the invention comprising a fixed part coming to replace a rear shell of the portable apparatus.

The device 100 equipping the apparatus 102 comprises a fixed part 106 arranged in order to be substituted for a rear shell normally equipping the portable user portable apparatus 102.

This fixed part 106 comprises a connection device 902 intended to be enclosed in the portable apparatus 102 and to implement the necessary electrical connections for interfacing the detection layers 408 and 410 of the foldable part 104 of the accessory 100 with the control and processing modules of the portable apparatus 102. The device 100 therefore comes in the form of an accessory which is an integral part of the portable apparatus 102 to which it contributes additional functions of capacitive detection.

FIG. 10 shows a representation of the apparatus 102 from FIG. 9, set on a surface 1002, such as a table, where the foldable part 104 is open so as to obtain a touch screen keyboard assembly which allows performing “hovering” type controls for games, for example directly with the user's hand 1004 or finger. These controls can include a joystick control by inclination of the user's hand 1004 above the foldable part 104 in order to direct an object displayed on the screen 110 and can do so without hiding the screen with the hand 1004.

FIG. 11 shows a representation of the apparatus 102 from FIG. 9, set on the surface 1002, such as a table, where the foldable part 104 forms an angle β greater than or equal to 90° with the screen 110 of the apparatus 102.

The screen 110 of the user apparatus 102 is provided with a capacitive detection layer/pad in order to detect with and/or without contact one or more command objects, such as a hand with one or more fingers towards the surface involved.

The detection of the hand 1004 by both the inner layer and by the detection layer of the display screen 110 serves to implement a detection volume formed between the foldable part 104 and the display screen 110.

Of course, the invention is not limited to the examples which were just described and many improvements could be made to these examples without leaving the scope of the invention. 

1. A device for a portable electronic user apparatus comprising a foldable part in order to cover at least one part of said user apparatus when it is folded onto said user apparatus, characterized in that said foldable part comprises at least two detection layers, each guarded at one guard potential and comprising at least one capacitive detection electrode: a first of said layers being arranged to perform a capacitive detection function of at least one command object located on one side of said foldable part; and a second of said layers being arranged to perform a capacitive detection function of at least one command object located on another side of said foldable part; in order to trigger a function in said user apparatus.
 2. The device according to claim 1, characterized in that each of said first and second layers, is configured for being activated for detection in turn, depending upon a relative position of the foldable part with respect to the user apparatus, whereby for a given position of said foldable part just one of said layers performs the detection function.
 3. The device according to claim 1, characterized in that it comprises at least one guard plane arranged between the first and second detection layers of the foldable part and configured for being placed at guard potential in order to guard at least one of said first and second detection layers during the detection of at least one command object.
 4. The device according to claim 3, characterized in that it comprises a single guard plane arranged between the first and second detection layers of the foldable part in order to guard each of said detection layers.
 5. The device according to claim 1, characterized in that each of said first and second detection layers is configured for performing in turn the role of: either the detection function; or a guard function for the other of said capacitive detection layers by being placed at an alternating guard potential (V_(G)); where the function performed by each of said layers depends on a relative position of said foldable part relative to said user apparatus.
 6. The device according to claim 1, characterized in that it additionally comprises at least one means of control to determine, depending on a position of the foldable part, which of the detection layers performs the detection function in order to activate the electrodes from said detection layer in a measurement mode.
 7. The device according to claim 5, characterized in that the means of control is further arranged in order to control placing the electrodes from the other electrode layer at the guard potential (V_(G)) in order to perform the guard function.
 8. The device according to claim 6, characterized in that the control means comprises a means of measurement of the position of the foldable part.
 9. The device according to claim 1, characterized in that at least one detection layer is arranged in order to perform a detection of at least one command object with or without contact.
 10. The device according to claim 1, characterized in that it is removable and includes at least one means of connection to the user apparatus.
 11. The device according to claim 10, characterized in that the means of connection is incorporated in a portion of a shell connected to the foldable part and arranged in order to be substituted for or arranged on a rear shell of the user apparatus.
 12. The device according to claim 1, characterized in that it is an integral part of the user apparatus.
 13. The device according to claim 1, characterized in that the foldable part comprises at least one transparent area and at least one of the detection layers comprises, at said transparent area, electrodes made of a transparent material.
 14. The device according to claim 1, characterized in that the foldable part comprises at least one opaque area and at least one of the detection layers comprises, at said opaque area, electrodes made by PCB technology.
 15. The device according to claim 1, implemented for the user apparatus provided with a screen, characterized in that the foldable part is configured in order to be positioned on or against said screen when it is folded.
 16. A portable computer user apparatus comprising the device according to claim
 1. 17. A method of providing object detection for a portable electronic user apparatus, comprising: covering at least a part of said user apparatus with a foldable part; detecting objects using a first detection layer on a first side of the foldable part while guarding the first detection layer with a guard potential; detecting objects using a second detection layer on a second side of the foldable part while guarding the second detection layer with the guard potential; and triggering a function in said user apparatus based on the detection of the objects.
 18. The method according to claim 17, further comprising activating the first and second detection layers for detection in turn, depending upon a relative position of the foldable part with respect to the user apparatus, whereby for a given position of said foldable part just one of said layers performs the detection function.
 19. The method according to claim 17, maintaining a plane at the guard potential between the first and second detection layers of the foldable part in order to guard at least one of said first and second detection layers during the detection of at least one command object.
 20. The method according to claim 19, further comprising forming a single guard plane arranged between the first and second detection layers of the foldable part in order to guard each of said detection layers. 